Autonomous vehicles and vehicles having driver assistance features, such as lane tracking and self-parking, require steering systems responsive to controller commands. Conventional hydraulic steering does not enable the implementation of driver assistance features and autonomous steering. One approach to addressing this concern is to equip vehicles for which such features are desired with electric-only power steering assist, relying exclusively on electric motors to provide the necessary steering input. However, completely electrical steering systems require more power than can practically be provided with 12 volt direct current (“12 V”) electrical architecture common to most vehicles. In particular, a 12 V motor is unable to provide sufficient steering assist for large passenger vehicles and commercial vehicles. Not having an electrically controlled steering system is an impediment to providing autonomous large passenger vehicles and commercial vehicles.